Paints and other items exposed to sunlight have a tendency to fade. It is desirable for manufacturers who are using such items to know how fade-resistant a given product is. Certain tests can be made by exposure to sunlight. However, this generally can be done only in certain geographic locations. Accordingly, various test apparatus have been developed utilizing artificial lights, such as carbonarc or xenon lamps. One commercially successful line of such artificial light testing systems is manufactured and sold by Atlas Electric Devices of Chicago, Ill. under its trademark "WEATHER-OMETER", and reference is made particularly to the C-Series "WEATHER-OMETER" testing apparatus.
Such prior art testing apparatus have worked very well, but have been expensive to manufacture and to operate. In order to ignite the Xenon lamp and to be able to control a wattage range of such apparatus, it has been necessary to use a plurality of components, specifically a main reactor, an auxiliary reactor, a voltage booster transformer, and four 40 MFD capacitors. In such prior art apparatus the main reactor was used as the primarily voltage limiting agent to the Xenon lamp after ignition, thus enabling and obtaining the minimum wattage on the order of 2 KW-2.2 KW.
The voltage booster transformer was used to increase the voltage to the Xenon lamp by approximately 50 to 60 volts AC depending somewhat on the line voltage, and thus to help ignite the Xenon lamp and also to obtain increased wattage once the lamp has been ignited.
The auxiliary reactor was used as a shunt across the main reactor in order to increase the inductive reactance, and thus to increase the voltage to the Xenon lamp. This also increased the wattage to the lamp. The auxiliary reactor was shunted across the main reactor by the use of a proportional controlled silicon controlled rectifier (SCR) circuit.
The four 40 microfarad capacitors were used to obtain higher wattage ranges by connecting them across the Xenon lamp after ignition, and thus to increase the voltage across the lamp. As is known, the capacitors are charged to peak voltage, i.e. effective value times 1.414, thus increasing the wattage.